This is the story of a bird flu type epidemic that isn't prevented---with a 25% kill rate and a very rapid spreading ability through air and objects touched. The reviews didn't like it in some cases because the emotional life of the characters was sacrificed to tell the story of the science, but that's just why we liked it. It did an excellent job of explaining how and why and epidemic spreads, and how it might be stopped, and how some unscrupulous people might try to profit from it. Because it is so lethal the characters do die, even some "name" actors. You will definitely think twice about touching things and your face for a while afterwards!
And of course there are "stories" of main characters to follow, it's by no means a documentary, but you do learn a lot.
Periodically it flashes back to show how it began, including right at the very very end.